Chromium (total)
CTWC - Shoreline Region-Guilford System
Chromium is a naturally occurring metal, but industrial uses can elevate its levels in water. One form, hexavalent chromium, causes cancer. Total chromium is not a good indicator of the amount of hexavalent chromium in drinking water.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | ND | 2 | 0 | ND |
| 2019 | ND | 4 | 0 | ND |
| 2020 | ND | 6 | 0 | ND |
| 2021 | ND | 2 | 0 | ND |
| 2022 | ND | 3 | 0 | ND |
| 2023 | ND | 8 | 0 | ND |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EPA Maximum Contaminant
Level (MCL): 100 ppb
The legal limit for total chromium, established in 1991, was based on a 1958 toxicity study in laboratory animals, and applies to both the less-toxic trivalent chromium and the more-toxic hexavalent chromium forms of this compound. This limit does not protect against the risk of cancer from ingestion of hexavalent chromium.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-03-30 | CA11463IOCR | ND |
| 2018-03-30 | CA11466IOC1 | ND |
| 2019-01-30 | IOC1 200520057 | ND |
| 2019-02-27 | IOCR 200523002 | ND |
| 2019-06-24 | IOC1 200537625 | ND |
| 2019-07-10 | IOC1 200539998 | ND |
| 2020-01-20 | IOC1 200563509 | ND |
| 2020-01-21 | IOC1 200563516 | ND |
| 2020-01-28 | IOC1 200564212 | ND |
| 2020-02-11 | IOC1 200565799 | ND |
| 2020-02-11 | IOCR 200565797 | ND |
| 2020-02-25 | IOC1 200567275 | ND |
| 2021-09-30 | I300072093 300072096 | ND |
| 2021-09-30 | R300072099 300072102 | ND |
| 2022-08-15 | CM05636 | ND |
| 2022-08-29 | CM17830 | ND |
| 2022-08-29 | CM17831 | ND |
| 2023-02-13 | CN41858 | ND |
| 2023-02-13 | CN41859 | ND |
| 2023-09-12 | CO95874 | ND |
| 2023-09-12 | CO95875 | ND |
| 2023-09-12 | CO95877 | ND |
| 2023-10-12 | CP23629 | ND |
| 2023-11-28 | CP55320 | ND |
| 2023-11-29 | CP56434 | ND |